Cam and follower mechanism



Feb. 8, 1938. TRApp I 2,107,456

CAM AND FOLLOWER MECHANISM Filed July 21, 1936 2 Sheets-Sheet l Feb. 8,1938;

G. J. 'IV'RAPP CAM AND FOLLOWER MECHANISM Filed July 21, 1956 &

2 Sheets-Sheet 2 .6- J-,Tra O Patented Feb. 8, 1938 UNITED STATES PATENTOFFICE England,

assignor to Automotive Products Company Limited, London, EnglandApplication July 21, 1936, Serial No. 91,775 In Great Britain July 31,1935 11 Claims.

This invention relates to cam and follower mechanism, such as thatemployed in fuel injection pumps, and it has for its object to providean improved construction of such mechanism which enables the design andmanufacture of fuel injection pumps and other machines employing cam andfollower mechanism to be considerably simplified. At the same time theinvention enables a saving in weight to be effected and furio therpermits the cam follower or followers to be removed from the body of thepump or equiv alent in an expeditious manner.

In a cam and follower mechanism having a housing member within which acam follower reciprocates slidably during its normal operation, thepresent invention is characterized by the fact that the housing memberis itself fitted in slides arranged transversely with respect to the follower travel, the arrangement being such that the housing member isinserted into place and removed therefrom in a direction substantiallyat right angles to the reciprocatory motion of the follower orfollowers.

In a cam and follower mechanism disposed within a structure serving asthe body of a pump or equivalent device, the invention further providesa housing having a hole forming parallel guiding surfaces for areciprocating sliding follower, said housing itself being fitted withinthe body by means of slides extending at right angles to the movement ofthe followers and, being inserted in place by movement along its slides.The housing may, of course, provide guiding surfaces for a plurality offollowers, which latter may conveniently be arranged in a singlestraight line, said housing preferably consisting of a. bar of metalformed with a series of transverse holes each fitted with areciprocatory cam follower, the edges of said bar being engaged betweena pair of parallel slides carried by the body of the mechanism wherebythe housing is slid into place in a direction at right angles to thefollower travel. If desired, the housing may be held against endwisedisplacement by a plate serving also to support a bearing for the camshaft, while in order to simplify the construction of the pump body orequivalent, said body may be formed with a transverse tunnel extendingthrough one or both ends of said body for the reception of the housingmember.

The invention further provides an improved construction of fuelinjection pump embodying the above described form of cam and followermechanism.

The accompanying drawings show examples of the invention as applied tofuel injection pumps,

while the lower part is formed integrally with a bottom H. The end wallsindicated at [2 and iii are bored to receive tubular bearing housings l4and I5 respectively, eachhaving a fixing plate shown at l6 and I!respectively. These accommodate rol1er bearings l 8 which rotatablysupport a cam shaft 19 formed with four cams 2t, 2H, 22 and 23. The camshaft is thus accommodated in a substantially rectangular compartment aswill be seen in Figure 3, the upper wall of which is constituted by apair of slide flanges 24 and 25 formed integrally with the body of thepump and by a housing member 26 extending for substantially the fulllength of the pump, as shown in Figure 1. modated slidably within alongitudinal tunnel extending completely through the body of the pumpand terminating in a hole 27 in the end l2 and a hole 28 in the end l3,said holes as well as the inwardly facing surfaces of the slide flanges24 and 25 being conveniently finished during manufacture by a broachingoperation.

As will be seen in Figures 2 and 3 the follower housing member 26 is ofsubstantially cruciform cross section, its two longitudinal edges beingformed with rectangular projections 29 and 33 which snugly engagecorresponding grooves in the body II] and thus prevent vertical movementof the housing member 26. The latter in the present instance is formedwith four rectangular holes SI, 32, 33 and 34 arranged in line withtheir axes vertical, said holes being immediately above thecorresponding cams 2i], 2!, 22 and 23 and providing guiding surfaces forcorresponding cam followers indicated at 35, 36, 31 and 38 in Figure 1.The cam followers which may conveniently be of the constructiondescribed in my copending application No. 64,377, each serves to actuatea pump plunger 39 in the usual manner and is normally urged to movedownwardly by a return The follower housing is in fact accomu spring 40.Access to the springs 43 and the associated parts of the pump can beobtained by the removal of the front cover ll having fixing screws 42.

It will be seen from Figure 1 that the upper parts of the plates i5 andii associated with the cam shaft bearings it completely overlap the endsof the housing members 263, and thus hold the latter positively in anendwise direction. When, however, attention to the follower housing 26is required, this part of the pump with its associated cam followers canbe drawn from the body in the direction indicated by the arrow A afterthe plate it has been removed, suitable precautions, of course, beingtaken for restraining the influence of the return springs as. The camfollowers may, if desired, be removed from the follower housing prior toits withdrawal from the pump body.

It will be understood that the follower housing 26 can be of anysuitable cross-section, and a modification is illustrated in Figure 5where the housing member is again in the form of a metal bar, the edges43 of which comprise parts of a common cylindrical surface generatedabout the longitudinal axis of the bar. In this way the housing can bevery readily manufactured, while the surfaces of the slide flanges 2iand25 supporting it can be accurately formed by a turning or boringoperation. In order to prevent rotation of the housing member 2t: a bolt44 can conveniently be fitted or a key or any other suitable meansemployed. In order that the follower housing 26 may be supported in thebest possible manner it is preferable that the slide flanges 24 and 25should extend for the whole length of the pump body or equivalent, butthis is not essential, as in some cases it is possible to support thehousing member only at isolated parts of its length, say for example itstwo ends only. Further, the invention may be applied to single cylinderpumps or to those incorporating in a single unit a plurality ofcylinders arranged in any desired formation, although of course, it isusual for the cylinders and consequently the cam followers to bearranged in a single straight line extending parallel with the cam shaftby which the followers are actuated. Any suitable construction of camfollower may. be used in conjunction with the housing according to theinvention, the cross section of the holes M to 3 1 being shaped anddimensioned accordingly. Thus, for instance, the housing is readiiyadaptable to the known form of follower which is cylindrical in shape,and is provided with a transverse pin engaging at its ends in keywaysformed in the housing. Further, any suitable means may be employed forretaining the follower housing in position within the pump body orequivalent, and, if desired, said housing may be composed of a number ofparts, for example a plurality of bars joined end to end or arrangedside by side. Thus the actual design and construction of the improvedfollower housing can deviate from the examples described, thecross-section of said member being arranged so that it keys with thepump body or equivalent so as to prevent all movement other than thatrequired for insertion.

It will be appreciated that the invention is by no means restricted tofuel injection pumps as it may equally well be applied to almost allmechanical units employing cam and follower mechanism, especially wherea plurality of followers are positioned within a confined space. Forexample, the invention is particularly suitable for use in engines andpumps other than fuel injection pumps, thus enabling the body castingsand the assembly of these units to be considerably simplified.

What I claim is:

1. In a cam and follower mechanism, disposed within a structure servingas the body of a pump or equivalent device, a housing having a holeproviding parallel guiding surfaces for a reciprocatory slidingfollower, said housing itself being fitted within the body by means ofslides extending at right angles to the movement of the follower, andbeing inserted in place by movement along its slides.

2. Cam and follower mechanism disposed within a structure serving as thebody of a pump or equivalent device, said mechanism comprising a camfollower housing which consists of a bar of metal formed with a seriesof transverse holes, each fitted with a reciprocatory cam follower, theedges of said bar being engaged between a pair of parallel slidescarried by the body of the mechanism whereby the housing is slid intoplace in a direction at right angles to the follower travel.

3. In a cam and follower mechanism, a body, a housinghaving a holeproviding parallel guide surfaces, a reciprocatory sliding followermounted in the hole, and means carried by the body and the housing forslidably mounting the housing within said body at right angles to themovement of the follower.

4. In a cam and follower mechanism, a structure serving as the body of apump, a housing having a plurality of holes each providing parallelguide surfaces, reciprocatory sliding followers in the holes, and slidescarried by the housing and adapted for mounting the housing within thebody to extend at right angles to the movement of the followers, saidhousing being adapted to be mounted in place by movement along theslides.

5. In a cam and follower mechanism, a body, a housing having a pluralityof holes arranged in a straight line with their axes parallel, each ofsaid holes providing parallel guide surfaces, a reciprocatory slidingfollower for each of said holes, and slides carried by the housing andadapted to cooperate with the body for slidably and removably mountingthe housing within the body to extend at right angles to the movement ofthe followers, said housing being adapted to be inserted in place bymovement along the slides.

6. In a cam and follower mechanism, a pump body, a cam shaft carried bythe body and mounted in a bearing, a housing having a hole providingparallel guide surfaces, a reciprocatory sliding follower in the hole,slides carried by the housing and adapted to cooperate with the body formounting the housing within the body at right angles to the movement ofthe follower, said housing being adapted to be inserted in place bymovement along'the slides, and a plate carried by the bearing forholding the housing and bearing in place in the body.

7. In a cam and follower mechanism, a body, a housing have a holeproviding parallel guide surfaces, a reciprocatory sliding followermounted the hole, and slides mounting the housing within the body atright angles to the movement of the follower, said housing beinginserted in place by movement along the slides, said slides extendingthe entire length of the housing.

8. In a cam and follower mechanism disposed within a structure servingas the body of a pump,

a housing cruciform in cross section and having a hole providingparallel guide surfaces, a reciprocatory sliding follower in the hole,and slides removably mounting the housing within the body at rightangles to the movement of the follower,

said housing being adapted to be mounted in place by movement along theslides.

9. In a fuel injection pump, a cam and follower mechanism comprising ahousing having a hole defining parallel guide surfaces, a reeipro catorysliding follower movably mounted in the hole, and slides fitting thehousing within the body at right angles to the movement of the follower,said housing being inserted in place by movement along the slides.

10. In a multi-cylinder fuel injection pump, a body, a cam and followermechanism including a crank shaft extending longitudinally of the body,a bar defining a housing and extending within the body parallel with thecam shaft, said bar having a plurality of holes each providing aparallel guide surface, a reciprocatory sliding follower in each of saidholes, and slides fitting the housing within the body at right angles tothe movement of the followers, said housing being inserted in place bymovement along the slides.

11. In a multi-cylinder fuel injection pump, a pump body, a cam andfollower mechanism including a cam shaft extending longitudinally of thepump body, a bar carried by the body and defining a housing extendingparallel with the cam shaft, said bar having a plurality of holes eachproviding parallel guide surfaces, a reciprocatory sliding followerwithin each of the holes, slides fitting the housing within the body ofthe pump at right angles to the movement of the followers, said housingbeing inserted in place by movement along the slides, a bearing at eachend of the cam shaft, and a plate at each end of the body for retainingthe cam shaft bearings and the housing in place.

GEORGE JOSEPH TRAPP.

